“…Approaches for data collection varied across the studies. In four of them, the data collection was performed using a structured interview plus vaccination card records [ 16 , 20 , 25 , 27 ], four studies used a structured interview/survey only [ 15 , 26 , 28 , 29 ] and five studies used administrative records [ 14 , 21 , 22 , 23 , 24 ].…”